<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Size</title>
    <style type="text/css">
        div {
            width: 800px;
            height: 500px;
            background-image: url('bg2.png'), url('bg1.jpg');
            background-image: url('bg1.jpg'), url('bg2.png');
        }
    </style>
</head>
<body>
<div></div>
</body>
</html>